This proposal is a request for the support of a Gas Chromatography-Mass Spectrometry (GC-MS) Clinical Research Resource. Under the proposed program visiting investigators from any existing or future General Clinical Research Center (GCRC) will be given the opportunity to bring their clinical research problems to this laboratory and receive training, technical assistance, and instrument access for the application of GC-MS to their research problems. Support for the program will provide these investigators with facilities and assistance to pursue GC-MS solutions to their research problems while giving them the necessary training and experience to enable them to subsequently utilize GC-MS facilities at their home institutions. The program will also offer the same opportunity to local GCRC investigators. In addition, it is proposed to conduct an annual 2-day workshop for GCRC program directors, principal investigators, and individual investigators to orient them to the capabilities and applicability of GC-MS to their research problems. Finally, the staff of this laboratory will offer assistance to GCRC program directors, investigators, and individual investigators in the establishment of GC-MS laboratories in relation to clinical research in their own institutions. For the investigator acquiring a new GC-MS instrument, the opportunity will be made available for him to install his own instrument at this site and receive training and assistance in applying GC-MS to his clinical research problems.